Conventionally, a semiconductor package structure including a semiconductor device such as an IC chip or the like mounted on a support substrate is known. Generally in such a semiconductor package structure, a semiconductor device such as an IC chip or the like is bonded to a support substrate via an adhesive material referred to as a “die attach”, and the semiconductor device is covered with an encapsulation material (formed of a sealing resin) for protection.
As the support substrate for the semiconductor package, any of various types of substrates including a printed circuit board, a ceramic substrate and the like is used. Especially recently, semiconductor packages using a metal substrate have been actively developed. A semiconductor package including semiconductor devices that are mounted on a metal substrate and connected with each other by lines to form a logical circuit has advantages of being high in electromagnetic shielding properties and thermal characteristics, and is now a target of attention as a highly reliable semiconductor package. Such a semiconductor package also has an advantage of having a high degree of designing freedom.
With a structure including semiconductor devices mounted on a support substrate, a plurality of semiconductor devices may be mounted on a large support substrate to produce a plurality of semiconductor packages in one process. In this case, the plurality of semiconductor packages formed on the support substrate are separated from each other after the production process and are provided as individual semiconductor packages. Such a structure of semiconductor package including semiconductor devices mounted on a support substrate has an advantage of being high in mass productivity.
Such semiconductor packages may be produced by use of a large metal substrate as the support substrate. The large metal substrate needs to have a certain level of rigidity in order to withstand processing. However, such a rigid substrate is not easily corrected if warped during the production process. Therefore, how to prevent the substrate from being warped during the production process is a problem to be solved. From the point of view of reliability of the semiconductor package, how to reduce the internal stress is also a problem to be solved.
Recently, stacked semiconductor packages including a plurality of semiconductor devices stacked on an organic substrate have been developed as described in Japanese Laid-Open Patent Publication No. 2010-278334. Especially in such a stacked semiconductor package, problems may occur during the production process thereof. First, an internal stress is caused when a resin layer used to insulate semiconductor devices from each other is cured, and the internal stress causes the warp, the residual stress declines the long-term reliability, and the layers, which are formed of different materials, are delaminated from each other. Second, a material of the support substrate, a resin material, silicon and a metal material used for lines used for the semiconductor package have coefficients of linear thermal expansion thereof not matched, and this causes the warp.